There was a time when the possibility of the earth revolving round the sun was the subject of much debate and, since there was a limited amount of evidence, it was basically a matter of belief and philosophy. Today there is no longer any serious debate, not least because we have actually travelled to the moon and walked around on it.
100 years ago the only way to understand the ‘moral’ laws that govern our social construct, was inductive reasoning; but over the last few years we have made amazing discoveries in genetics (popularised in “the selfish gene”), and how the brain works (read “The tell tale brain”) and a recent book “The braintrust” now argues that morality originates in the biology of the brain. It describes the “neurobiological platform of bonding” that, modified by evolutionary pressures and cultural values, has led to human styles of moral behaviour.
I am not saying that science has all the answers, but I am sure that it will bring new insights to the function of moral codes and explanations of how they can work even without recourse to the authority of a god figure to back them up. As an atheist it is important to understand that our moral code is just as strong and well based as that of any religious person.